This invention is related to printers, thermal printers, facsimile machines, and the like, which employ a roll of paper for recording information and, more particularly, to safety printing apparatus for printing onto a roll-fed media and for severing the media into image-bearing portions comprising, a roll of the media disposed between a supply point and an outlet point; printing means disposed between the supply point and the outlet point for printing images on the media; a removably closable lid; a cutting blade disposed under the lid between the printing means and the outlet point; pivoting means for supporting the cutting blade and for permitting the cutting blade to fall to a withdrawn safety position from the force of gravity; and means on the lid for moving the pivoting means and the cutting blade therewith whenever the lid is closed away from the safety position to an operating position.
Various types of roll-fed paper-recording devices, including printers, plotters, thermal printers, and facsimile machines, store a large roll of paper which is fed under a printing head or station of some type. In order to print a standard 8.5" by 11" document page, for example, an 11 inch section of the roll must be severed by a paper cutter which, in the better devices, is internal to the device. The cutter should be located between the printer head and the paper exit of the device, and must be sharp. Furthermore, the device should have an openable cover which exposes the paper path in the vicinity of the cutter, permitting the operator to replenish the paper roll and thread the leader of the new roll through the pinch rollers, paper guides, and cutter. As a result, it is difficult to design a practical printer, or the like, in which the operator does not bear some risk in contacting the sharp paper cutter whenever the paper roll must replenished.
Various techniques are known for housing or moving a paper cutter in a printer. For example, U.S. Pat. No. 1,643,583 described a paper cutter for a typewriter in which the rotary cutter head and its protective housing are rotatable about an axis away from the paper upon completion of each paper cutting operation. U.S. Pat. No. 3,925,786 describes a plotter having a paper cutter in which a cutting head on a cylinder inside a stationary housing rotates away from the paper by rotation of the cylinder upon completion of each paper cutting operation. U.S. Pat. No. 4,042,939 discloses a printer in which part of a paper cutter assembly is attached to the cover lid of the printer, the assembly including a cutter blade which is retracted from the paper by a solenoid upon completion of each paper cutting operation. U.S. Pat. No. 4,701,063 describes a printer with a rotary cutter blade which is supported by a fulcrum rotated by a spring actuator upon the completion of each paper cutting operation.
These prior patents fail to adequately address the problem of protecting the operator from the paper cutting blade while he accesses the paper path near the paper cutter during replenishment of the paper roll, for example. None of them discloses automatically taking special action at the time the operator gains access to the paper path through the printer, or upon opening the cover lid of the printer. Moreover, in each of these prior patents movement or retracting of the cutter is for the purpose of permitting printing or recording operations between cutting operations and was performed by powered actuators or similar devices. Accordingly, the retracting mechanism add significantly to the cost of the device. Where cost is a factor, therefore, they are simply omitted in the interest of economy.
Wherefore, it is an object of the invention to increase the safety with which printers, plotters, thermal printers, facsimile machines and the like may be operated, particularly during paper roll replenishment.
It is a further object of the invention to provide a safe printer or the like in which the paper cutting head automatically retracts to a protected position under the housing lip whenever the top cover is opened by the operator.
It is yet a further object of the invention to provide a means for automatically retracting the paper cutting head in a printer or the like below the housing lip whenever the top cover is opened without requiring any powered actuators.
It is an even further object of the invention to provide an automatic paper cutter head retracting device in a printer or the like which simply relies on gravity to retract the paper cutting head to a safe position with respect to the operator whenever he opens the top cover of the printer.
It is yet another object of the invention to provide an automatic paper cutter head retracting device in a printer or the like which retracts the paper cutting head to a safe position with respect to the operator and which is simple and inexpensive to include within the apparatus and not be omitted for cost savings sake.
Other objects and benefits of the invention will become apparent from the description which follows hereinafter when taken in conjunction with the drawing figures which accompany it.